Electronic Throttle Control (Etc) Indicator

The ETC indicator gives an indication to the vehicle operator when the ETC system, or a circuit or component of the system is inoperative. The ETC indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the PCM/ECM over the CAN data bus.

The ETC indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. Each time the ignition switch is turned to the ON position the ETC indicator is illuminated for about three seconds, but no longer than 15 seconds. The entire bulb test is a function of the instrument cluster. The instrument cluster will turn ON the ETC indicator for the following reasons:

• ETC Indicator Lamp-On Message  - Each time the cluster receives an electronic ETC indicator lamp-ON  message from the PCM/ECM, the ETC indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the PCM/ECM message. The indicator remains illuminated solid or continues to flash for about 12 seconds or until the cluster receives a lamp-OFF message from the PCM/ECM, whichever is longer. If the indicator is illuminated solid with the engine running the vehicle will usually remain drivable. If the indicator is flashing with the engine running the vehicle may require towing. A flashing indicator means the ETC system requires immediate service. The indicator will be extinguished when the ignition switch is turned to the OFF position.

The PCM/ECM continually monitors the ETC system circuits and sensors to decide whether the system is in good operating condition. The PCM/ECM then sends the proper lamp-ON or lamp-OFF message to the CCN. If the PCM/ECM sends a lamp-ON message after the bulb test, it indicates that the PCM/ECM has detected an ETC system malfunction or that the ETC system is ineffective. The PCM/ECM will store a DTC for any malfunction it detects.